/* * Copyright (c) 2005 The DragonFly Project. All rights reserved. * * This code is derived from software contributed to The DragonFly Project * by Matthew Dillon <dillon@backplane.com> * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name of The DragonFly Project nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific, prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ struct server_info { int fd; /* udp descriptor */ int server_state; /* -1 (no dns), 0 (dns good), or 1 (pkt good) */ int server_insane; /* insanity check */ int poll_sleep; /* countdown for poll (in seconds) */ int poll_mode; /* mode of operation */ int poll_count; /* number of polls in current mode */ int poll_failed; /* count of NTP failures */ struct sockaddr *sam; /* udp connection info */ struct sockaddr_storage sam_st; /* udp connection info (stor) */ char *target; /* target hostname or IP (string) */ char *ipstr; /* IP string */ /* * A second linear regression playing hopskip with the first. This * is maintained by the check function. */ struct server_info *altinfo; /* * Linear regression accumulator * * note: the starting base time is where all corrections get applied * to eventually. The linear regression makes a relative microseconds * calculation between the current base time and the starting base * time to figure out what corrections the system has made to the * clock. */ struct timeval lin_tv; /* starting real time */ struct timeval lin_btv; /* starting base time */ double lin_count; /* samples */ double lin_sumx; /* sum(x) */ double lin_sumy; /* sum(y) */ double lin_sumxy; /* sum(x*y) */ double lin_sumx2; /* sum(x^2) */ double lin_sumy2; /* sum(y^2) */ /* * Offsets are accumulated for a straight average. When a * correction is made we have to reset the averaging code * or follow-up corrections will oscillate wildly because * the new offsets simply cannot compete with the dozens * of previously polls in the sum. */ double lin_sumoffset; /* sum of compensated offsets */ double lin_sumoffset2; /* sum of compensated offsets^2 */ double lin_countoffset; /* count is reset after a correction is made */ /* * Cached results */ double lin_cache_slope; /* (freq calculations) */ double lin_cache_yint; /* (freq calculations) */ double lin_cache_corr; /* (freq calculations) */ double lin_cache_stddev; /* (offset calculations) */ double lin_cache_offset; /* last sampled offset (NOT an average) */ double lin_cache_freq; /* last frequency correction (s/s) */ }; /* * Polling modes and max polls for specific modes. Note that the polling * mode basically just effects the polling rate. It does not effect the * linear regression. */ #define POLL_FIXED 0 /* fixed internal (nom_sleep_opt seconds) */ #define POLL_STARTUP 1 /* startup poll for offset adjust (min) */ #define POLL_ACQUIRE 2 /* acquisition for frequency adjust (nom) */ #define POLL_MAINTAIN 3 /* maintainance mode (max) */ #define POLL_FAILED 4 /* failure state (nom) */ #define POLL_STARTUP_MAX 6 /* max polls in this mode */ #define POLL_ACQUIRE_MAX 16 /* max polls in this mode */ #define POLL_FAIL_RESET 3 /* reset the regression after 3 fails */ #define POLL_RECOVERY_RESTART 10 /* ->ACQ vs ->STARTUP after recovery */ /* * We start a second linear regression a LIN_RESTART / 2 and it * replaces the first one (and we start a third) at LIN_RESTART. */ #define LIN_RESTART 30 /* * A course correction is made if the time gets more then 2 minutes * off. */ #define COURSE_OFFSET_CORRECTION_LIMIT 120.0 typedef struct server_info *server_info_t; void client_init(void); void client_main(struct server_info **info_ary, int count) __dead2; void client_poll(server_info_t info, int poll_interval, int calc_offset_correction); void client_check(struct server_info **check, struct server_info **best_off, struct server_info **best_freq); void client_check_duplicate_ips(struct server_info **info_ary, int count); void client_manage_polling_mode(struct server_info *info, int *didreconnect); void client_setserverstate(server_info_t info, int state, const char *str); void lin_regress(server_info_t info, struct timeval *ltv, struct timeval *lbtv, double offset, int calc_offset_correction); void lin_reset(server_info_t info); void lin_resetalloffsets(struct server_info **info_ary, int count); void lin_resetoffsets(server_info_t info);
